Hydrorefining of petroleum crude oil and catalyst therefor



United States Patent Ofifice 3,159,919 Patented Feb. 16, 1965 3 169 919 HYDRGREFHNING E PRETROLE UM (IRUDE 9115 AND (IATALYST THEREFOR John a. Gatsis, Des Plaines, and William K. r. Glenn,

The present invention relates to a method for preparing a novel catalyst particularly adaptable for utilization in the process of hydrorefining petroleum crude oils, heavy vacuum gas oils, heavy cycle stocks, crude oil residuum, topped crude oils, and other hydrocarbon mixtures boiling above the gasoline boiling range. More specifically, the present invention involves a process for hydrorefining a heavy hydrocarbon charge stock for the purpose of effecting the removal of nitrogen and sulfur therefrom, and affords unexpected advantages When employed for the destructive removal of organo-metallic contaminants and/or the conversion of pentane-insoluble hydrocarbonaceous material within a petroleum crude oil.

Petroleum crude oils, and the heavy hydrocarbon fractions and/or distillates obtained therefrom, particularly vacuum gas oils and topped crudes, contain nitrogenous and sulfurous compounds in large quantities. In addition, petroleum crude oils generally contain detrimental quantities of organo-metallic contaminants which possess the tendency to exert deleterious effects upon the catalyst utilized in various processes to which the crude oil, topped crude oil, or heavy hydrocarbon fractions may ultimately be subjected. The more common of such metallic contaminants are nickel and vanadium, generally existing in concentrations in excess of 50 p.p.m., although other metals including iron, copper, etc., are often present. These organo-metallic contaminants may occur Within the petroleum crude oil in a variety of forms; they may exist as metal oxides or sulfides, introduced into the crude oil as metallic scale or particles; they may be present in the form of soluble salts of such metals; usually, however, they exist in the form of organo-metallic compounds such as metal porphyrins and the various derivatives thereof. Although the metallic contaminants existing as oxide or sulfide scale may be removed, at least in part, by a relatively simple filtering technique, and the water-soluble salts are at least in part removable by washing and a subsequent dehydration procedure, a much more severe treatment is required to eifect the destructive removal of the organo-metallic compounds, particularly to the degree necessary to produce a crude oil or heavy hydrocarbon fraction which is suitable for further processing.

In addition to the organo-metallic contaminants, including metal porphyrins, crude oils contain greater quantities of sulfurous and nitrogenous compounds than are generally found in lighter, normally liquid hydrocarbon fractions such as gasoline, kerosene, light gas oil, etc. For example, a Wyoming sour crude, having a gravity of 23.2" API at 60 F., contains about 2.8% by Weight of sulfur and 2700 ppm. of nitrogen. The nitrogenous and sulfurous compounds are readily converted, upon being subjected to catalytic hydrorefining, into hydrocarbons, ammonia and hydrogen sulfide; similarly, any oxygenated compounds are converted into water and the hydrocarbon counterpart. However, the reduction in the concentration of the organo-metallic contaminants is not as easily achieved, and to the extent that the same no longer exert a detrimental effect, particularly with respect to further processing of the petroleum crude oil. Notwithstanding that the total concentration of these metallic contaminants may be relatively small, for example, less than about 10 ppm. of metallic porphyrins, calculated as the elemental metals, subsequent processing techniques will be adversely affected thereby. Thus, when a hydrocarbon charge stock containing metals in an excess of about 3.0 ppm, is subjected to a cracking process for the purpose of producing lower-boiling components, the metals become deposited upon the catalyst employed, steadily increasing in quantity until such time as the composition of the catalytic composite is changed to the extent that undesirable results are obtained. That is to say, the composition of the cracking catalyst is controlled with respect to the nature of the charge stock being processed and to the desired product quality and quantity. This composition is changed considerably due to the deposition of the metallic contaminants thereupon, the changed composite resulting in changed catalytic characteristics. This particular effect is highly undesirable with respect to the cracking process, since the deposition of metallic contaminants upon the catalyst tends to result in a lesser quantity of valuable liquid product, in large amounts of hydrogen and coke, the latter also producing a relatively rapid degree of catalyst deactivation.

In addition to the foregoing contaminating influences, crude oils and other heavier hydrocarbon fractions contain excessive quantities of pentane-insoluble material. For example, the Wyoming sour crude described above consists of about 8.3% by weight of pentane-insoluble asphaltenes which are hydrocarbonaceous compounds considered to be coke-precursors having the tendency to become immediately deposited within the reaction zone and onto the catalytic composite in the form of a high molecular weight, gummy residue. Since the deposition of this material constitutes a large loss of charge stock, it is economically desirable to convert such asphaltenes into useful hydrocarbon oil fractions, thereby increasing the liquid yield based upon the quantity of oil charged to the process.

The object of the present invention is to provide a much more efficient process for hydrorefining heavier hydrocarbonaceous material, and particularly petroleum crude oil containing pentane-insoluble asphaltenes, utilizing an unsupported catalyst prepared in a particular manner. The term hydrorefining, as employed herein, connotes the catalytic treatment, in an atmosphere of. hydrogen, of a hydrocarbon fraction or distillate for the purpose of eliminating and/or reducing the concentration of the various contaminating influences previously described. As hereinbefore set forth, metals are generally removed from the charge stock by deposition of the same on the catalyst employed, and asphaltenes are deposited inthe form of coke. This increases the amount of catalyst Within the reaction zone, actively shields the catalytically active surfaces and centers from the material being processed, and precludes the utilization of any efficient fixed-bed catalyst system for processing such highly contaminated crude oil. Various moving-bed processess, employing catalytically active metals deposited upon a carrier material consisting of silica and/or alumina, for example, or other refractory inorganic oxide material, such as alumina-zirconia, are extremely erosive, causing slurry process, which catalytic material will not effect extensive erosion or corrosion of the reaction system. The present process yieldsa liquid hydrocarbon product which is more suitable for further processing without experiencing the diiiiculties otherwise resultingfrom the presence of the foregoing contaminants; The present invention affords a process which is particularly advantageous for eifecting the conversion of the organo-metallic' compounds without significant product yield loss, which simultaneous ly converting pentane-insoluble material into pentanesoluble liquid hydrocarbons.

In a broad embodiment, the present invention relates to a hydrorefining catalyst which comprises a colloidal suspension of molybdenum blue in a hydrocarbon.

Another broad embodiment of the present invention encompasses a method of preparing a hydrorefining catalyst which method comprises forming a solutionof molybdenum blue, commingling said solution with a hydrocarbon and distilling the resulting mixture to remove the solvent, thereby forming a colloidal suspension of said molybdenum blue in said hydrocarbon.

More specifically, the present invention is directed toward a process for hydrorefining a hydrocarbon charge stock which comprises forming an alcohol solution of molybdenum blue, commingling said solution with said charge stock, distilling the resulting mixture to remove said alcohol, forming a colloidal suspension of said molybdenum blue in said charge stock, and thereafter reacting said colloidal suspension with hydrogen at a temperature above about 225? C. and at a pressure greater than about 500 pounds per square inch gauge.

A more limited embodiment of the present invention involves a process for hydrorefining a petroleum crude oil containing pentane-insoluble asphaltenes, which process comprises forming an alcohol solution of molybdenum blue, commingling said solution with said petroleum crude oil, distilling the resulting mixture to remove said alcohol and to form a colloidal suspension of from about 0.1%

to about 10.0% by weight of said molybdenum blue, cal-. culated as elemental molybdenum, in said petroleum crude oil and thereafter reacting said collodial suspension with hydrogen at a temperature within the rangevof from about 225 C.,to about 550 C. and at a pressure of from about 500 to about.5000 pounds per square inch gauge.

From the foregoing embodiments, it is noted that the method of the present invention involves the preparation of a colloidally dispersed, unsupported catalyst within the hydrocarbonaceous material from which the contaminate ing influences are to be removed. The catalyst is molybdenum blue, and is employed as a solution in an amount such that the colloidal suspension, or dispersion, which results when the particular solvent is removed, comprises from about 0.1% to about 10.0% by weight, calculated, however, as the elemental metal. Briefly, the process is effected, .as hereinafter set forth in the specific examples, by initially dissolving the desired quantity of molybdenum blue in a suitable solvent. The resulting solution is then intimately .commingled with'the petroleum crude oil, or

other heavy hydrocarbon fraction, from which resulting mixture the solvent is removed, for example, by heating the mixture at a temperature sufiiciently high to remove the same by distillation. Typical alcohols, suitable for utilization in preparing the-solution of molybdenum blue, include isopropyl alcohol, isopentyl alcohol, methyl alcohol,,amyl alcohol, and other alcohols containing up to and including-about ten carbon atoms per molecule. Other suitable solvents for the molybdenum blue, although not necessarily yielding equivalent results, include water, and esters and ketones such as acetone, methyl ethyl ketone, methyl acetate, ethylacetate, etc. The mixture of the alcohol solution of molybdenum blue, for example, and the petroleum crude oil is heated at a temperature 4 below about 310 C., and preferably less than C. for the purpose of distilling the alcohol, leaving the molybdenum blue as a colloidal suspension dispersed within the crude oil. Temperatures above about 310 C.

tend to result in premature cracking reactions whereby the effectiveness of the process to convert pentane-insoluble asphaltenes becomes adversely affected. The colloidal dispersion is then passed into a suitable reaction zone maintained at a temperature within the range of from about 225 C. to about 500 C. and under a hydrogen pressure within the range of from about 500 to about 5000 pounds per square inch gauge.

The process may be conducted as a batch-type procedure or in an enclosed vessel through which the colloidalsuspension is passed; when eifected' in a continuous manner, the process may be conducted in either upward flow or downward flow. Normally liquid hydrocarbons are separated from the total reaction zone product efiluent by any suitable means, for example, through the use of a centrifuge or settling tanks, atleast a portion of the resulting catalyst-containing sludge being combined with fresh petroleum crude oil, and recycled through the reaction zone. In order to maintain a high degree of catalytic activity, it is preferred that at least a portion of the catalyst-containing sludge be removed from the process prior to combining the remainder with fresh crude oil. The precise quantity of catalyst-containing sludge removed from the process will be dependent upon the desired degree of contaminant removaL, However, it is desirable to add a quantity of fresh molybdenum blue to the petroleum crude oil to compensate for that quantity of molybdenum, calculated as the elemental metal, removed from the catalyst-containing sludge, maintaining the concentration of the dispersed material within the crude oil from about 0.1% 'to about 10.0% by weight.

Although the molybdenum blue may be prepared in situ, that is, within the petroleum crude oil-or heavy hydrocarbon fraction to be processed, the preferred method of conducting the process of the present invention comprises initially preparing the molybdenum blue separate from the crude oil. It is'further understood that the precise means for manufacturing the molybdenum blue is not considered alimiting feature upon the present invention. For example, a watery ammonium molybdate solution may be acidified with sulfuric acid and treated with hydrogen sulfide at ambient temperature. The resulting solution is filtered free from sulfur and dialyzed for several days against running water; until free from sulfuric acid and ammonium sulfate. The dialyzed solution is evaporated and the residue is dried on a steam bath, the. dried residue being ground to a talc-like powder and dispersed within the crude oil as the alcohol solution. In the following specific examples, the molybdenum blue is prepared by the reduction of molybdate withtrivalent molybdenum, obtained by'reduction of molybdate in a Jones reductor; this procedure is set forth in detail in the Journal oftheAmerican Chemical Society, volume 64, pages 2543-2545 (1942) The following examples are given to illustrate thev processof the present invention and the effectiveness thereof in removing nickel and'vanadium contaminants from a petroleum crude oil, and in. converting the pentane-insoluble asphaltenes while simultaneously effecting the through the use of the present invention, was a Wyoming sour crudeoil having a gravity of 23.2 API at 60 F., containing about 2.8% by weight of sulfur, approximately 2700 p.p.m. of nitrogen, 18 ppm. of nickel and 81 p.p.m. of vanadium as metal porphyrins, calculated as the elemental metal. In addition, the sour crude consisted of about 8.3% by weight of pentane-insoluble asphaltenes. As hereinafter indicated, the process of the present invention not only eifects conversion of a significant proportion of pentane-soluble asphaltenes, but also results in a substantial production of lower-boiling hydrocarbons as indicated by an increase in the gravity, API at 60 F., of the normally liquid hydrocarbon portion of the total reaction zone product eflluent.

Example I In this example, 6.86 grams of molybdenum blue, pre pared in accordance with the article appearing in the Journal of The American Chemical Society, was added to 200 grams of the Wyoming sour crude, resulting in a colloidal suspension comprising about 2.0% by Weight of molybdenum. The mixture was placed in a rotating autoclave, pressured to 100 atmospheres with hydrogen, and heated to a temperature of 400 F., the final pressure being about 212 atmospheres. These conditions were maintained for a period of 8 hours, after which time the contents of the rotating autoclave were subjected to centrifugal separation. The resulting normally liquid hydrocarbon portion of the product efiluent indicated concentrations of 1990 p.p.m. of nitrogen, 0.93% by wei ht of sulfur, 2.41% by Weight of pentane-insoluble asphaltenes, 1.5 p.p.m. of nickel and 2.0 p.p.m. of vanadium. The specific gravity of the normally liquid hydrocarbon portion, API at 60 F., was 29.4.

Example ll Molybdenum blue, in an amount of 6.86 grams, was added to isopentyl alcohol and heated on a steam bath. The alcohol solution was added dropwise to 250 grams of the Wyoming sour crude, accompanied by mechanical stirring, and heating to distill the alcohol as the same was added. Following the addition of the alcohol solution of molybdenum blue, the sample was distilled to remove that portion of the Wyoming sour crude boiling within normal gasoline boiling range. The resulting colloidal suspension, containing 1.9% by weight of molybdenum, calculated as the element, was placed in a rotating autoclave and pressured to 100 atmospheres with hydrogen. The temperature was increased to a level of 400 C., increasing the pressure to 193 atmospheres, which conditions were maintained for a period of 8 hours. The normally liquid product etliuent, following separation from the catalyst-containing slud e in a centrifugal separator, indicated 1480 p.p.m. of nitrogen, 0.72% by weight of sulfur, 0.91% by weight of pentane-insoluble asphaltenes, 0.3 p.p.m. of nickel and 2.0 p.p.m. of vanadium, the gravity, AM at 60 F., being 28.4.

Example III 6.86 grams of molybdenum blue were added to 500 grams of methanol and heated on the steam bath. The methanol solution of molybdenum was added to 225 grams or the sour crude, and the resulting mixture distilled to remove the methanol and gasoline boiling range portion of the crude oil. The resulting colloidal suspension, containing about 1.4% by weight or" molybdenum, calculated as the element, was placed Within the rotating autoclave and pressured to 100 atmospheres with hydrogen. The temperature was increased to a level of 400 C., the final pressure being 195 atmospheres, and the conditions were maintained for a period of 8 hours. Following separation in a centrifugal separator, the normally liquid product, having a gravity, API at 60 F., of 31.5, indicated 155 p.p.m. of nitrogen, 0.15% by weight of sulfur, 0.24% by weight of pentane-insoluble asphaltenes, 0.4 p.p.m. of nickel and 0.08 p.p.m. of vanadium.

6 Example IV Molybdenum blue, in an amount of 6.86 grams, was dissolved in water, the solution being added dropwise to 225 grams of the sour crude. Following reaction with hydrogen at 400 C. and 188 atmospheres for a period of 8 hours, the catalyst-containing sludge was separated from the normally liquid portion of the total product efiluent. Analyses of the latter indicated 154 p.p.m. of nitrogen, 0.17% by weight of sulfur, 0.42% by weight of asphaltenes, less than 0.03 p.p.m. of nickel, 0.09 p.p.m. of vanadium and had a specific gravity of 31.4 API at 60 F.

The foregoing examples and specification clearly indicate the method of efiecting the process of the present invention and the preparation of the catalyst employed therein. It should be noted that there has been a significant degree of elimination and/or conversion of the various contaminating influences, particularly when the molybdenum blue is added to the crude oil in the form of an alcohol solution thereof, and to the extent that the crude oil is extremely suitable for further processing. The benefits afforded a process of hydrorefining petroleum crude oils, and heavier hydrocarbon fractions, through the use of the method of the present invention, will be readily recognized by those possessing skill in the art of petroleum refining.

We claim as our invention:

1. A hydrorefining catalyst consisting essentially of a colloidal suspension of molybdenum blue in a hydrocarbon.

2. A hydrorefining catalyst consisting essentially of a colloidal suspension of from about 0.1% to about 10.0% by weight of molybdenum blue, calculated as elemental molybdenum, in a hydrocarbon.

3. A method of preparing a hydrorefining catalyst which comprises forming a solution consisting essentially of molybdenum blue in a solvent for the latter, cornmingling said solution with a hydrocarbon and distilling the resulting mixture to remove the solvent, thereby providing a colloidal suspension of said molybdenum blue in said hydrocarbon.

4. The method of claim 3 further characterized in that said solvent is water.

5. The method of claim 3 further characterized in that said solvent is an oxygen-containing organic compound selected from the group consisting of alcohols, ketones and esters.

6. A method of preparing a hydrorelining catalyst which comprises forming a solution consisting essentially of molybdenum blue and an alcohol having less than about 11 carbon atoms per molecule, commingling said solution with a hydrocarbon and heating the resulting mixture to remove said alcohol and to provide a colloidal suspension of molybdenum blue in said hydrocarbon.

7. The method of claim 6 further characterized in that said colloidal suspension comprises from about 0.1% to about 10.0% by weight of molybdenum blue, calculated as elemental molybdenum.

8. A process for hydrorefining a hydrocarbon charge stock which comprises forming a solution of molybdenum blue in a solvent for the latter, commingling said solution with said charge stock, distilling the resulting mixture to remove the solvent and to form a colloidal suspension of from about 0.1% to about 10% by weight of said molybdenum blue, calculated as elemental molybdenum, in said charge stock, and thereafter reacting said colloidal suspension with hydrogen at a temperature from about 225 C. to about 500 C. and at a pressure of from about 500 to about 5000 pounds per square inch gauge.

9. The process of claim 8 further characterized in that said solvent is water.

10. The process of claim 8 further characterized in that said solvent is an oxygen-containing organic compound selected from the group consisting of alcohols, esters and ketones.

11. A process for hydrorefining a petroleum crude oil prises forming an alcohol solution of molybdenum blue,

commingling said solution with said petroleum crude oil, distilling the resulting mixture to remove said alcohol and to form a colloidal suspension of from about 0.1% to about 10.0% by weight of said molybdenum blue, calculated as elemental molybdenum, in said petroleum crude oil and thereafter reacting said colloidal suspension with hydrogen at a temperature within therange of from about 225 C. to about 500 C. and ata pressure of from about 500-to about 5000 pounds per square inch gauge.

References (Jilted in the file of this patent UNITED STATES PATENTS 

1. A HYDROREFINING CATALYST CONSISTING ESSENTIALLY OF A COLLOIDAL SUSPENSION OF MOLYBDENUM BLUE IN A HYDROCARBON. 